1. Design for density, not pixels
Design for the pixel density of the device, not raw pixels.
2. Use 8dp increments
Spacing in increments of 8 creates consistency across devices.
3. Remove lines and boxes
Boxes and lines dividing content could often be replaced with margin.
4. Pay attention to contrast
Contrast draws the users eye and improves accessibility.
5. Familiarity is good
Be creative only within the confines of current design norms.
6. Use color weight to establish hierarchy
Assign different levels of importance to elements using color weight.
7. Avoid using more than two typefaces
Two typefaces (with families) is usually enough.
8. Recognition, not recall
Minimize the users memory load by making objects and actions visible.
9. Don't slow me down
Be purposeful with animations; do not add unnecessary delay.
10. Less is more
Every added element competes with the relevant information on a page.